/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.web.filter;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.util.Assert;
import org.springframework.web.util.WebUtils;

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

/**
 * A response wrapper used for the implementation of
 * {@link RelativeRedirectFilter} also shared with {@link ForwardedHeaderFilter}.
 *
 * @author Rossen Stoyanchev
 * @since 4.3.10
 */
final class RelativeRedirectResponseWrapper extends HttpServletResponseWrapper {

    private final HttpStatus redirectStatus;


    private RelativeRedirectResponseWrapper(HttpServletResponse response, HttpStatus redirectStatus) {
        super(response);
        Assert.notNull(redirectStatus, "'redirectStatus' is required");
        this.redirectStatus = redirectStatus;
    }

    public static HttpServletResponse wrapIfNecessary(HttpServletResponse response,
                                                      HttpStatus redirectStatus) {

        RelativeRedirectResponseWrapper wrapper =
                WebUtils.getNativeResponse(response, RelativeRedirectResponseWrapper.class);

        return (wrapper != null ? response :
                new RelativeRedirectResponseWrapper(response, redirectStatus));
    }

    @Override
    public void sendRedirect(String location) {
        setStatus(this.redirectStatus.value());
        setHeader(HttpHeaders.LOCATION, location);
    }

}
